1. Field of the Invention
The present invention relates to a cowling unit of a motorcycle having an air introducing opening at the front of a cowling and a radiator in the cowling behind the air introducing opening and, in particular, a cowling unit capable of reducing running resistance.
2. Description of the Background Art
Japanese Utility Model Laid-Open No. S59-30781 shows an example of a cowling unit. In this example, side radiators are arranged on both sides of a cowling and take air from an air introducing opening at the front of the cowling and discharge the air after cooling the side radiators outside a vehicle from air discharging ports overlapping the side radiators. Japanese Utility Model Laid-Open No. H4-52990 discloses an example in which air guide plates are arranged on both sides of the air introducing port of a cowling to guide air to a rider side.
In the case of a radiator of the type introducing air from an air introducing opening to cool a radiator, in order to improve cooling efficiency, it is conceived to increase the opening area of the air introducing opening. However, if the opening area of the air introducing opening is increased, members arranged behind the air introducing opening such as a front fork or the like are more exposed to air and increase running resistance. Accordingly, it is necessary to reduce the running resistance at the same time when the opening area of the air introducing opening is increased. It is difficult to ensure the clearance between the lower portion of the headlight and the front fender of the cowling and hence the shape of the cowling is also constrained. In this point, the circumstances are the same, to one degree or another, even in the case where a motorcycle is provided with side radiators.
It is therefore an object of the present invention to reduce running resistance and to improve cooling efficiency. In order to solve the above problem, a cowling unit of a motorcycle in accordance with the first aspect of the present invention is characterized in that, in the motorcycle comprising a cowling covering the front portion of a vehicle body and both sides of an engine and having an air introducing opening at its front portion and a radiator mounted in the cowling at the back of the air introducing opening, the present invention utilizes left and right air guide walls mounted on the cowling and overhanging the upper portion of the air introducing opening from left and right sides to cover a pair of left and right front forks at their front portions.
The second aspect is characterized in that, according to the first aspect, the air guide walls guide air flowing toward the radiator. The third aspect is characterized in that, according to the second aspect, the radiator is a side radiator.
According to the first aspect, air guide walls overhanging the air introducing port and covering the front portion of the front forks are mounted on the left and right sides of the upper portion of the cowling and, hence, even if the air introducing opening is enlarged, the air guide walls can reduce the degree of exposure of the front forks to prevent an increase in running resistance. Accordingly, this cowling can prevent an increase in running resistance and enlarge the air introducing opening at the same time to improve cooling efficiency to the radiator.
According to the second aspect, since the air guide walls guide running air toward the radiator, they can further improve cooling efficiency. According to the third aspect, since the side radiator is provided, it can reduce the running resistance caused by the radiator. Accordingly, the opening area of the air introducing opening can be further enlarged to further improve cooling efficiency.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.